Dish assemblies for collecting and concentrating solar radiation are known which concentrate direct solar radiation in excess of 1000 times by the reflection of incoming direct or beam radiation. These systems automatically track the sun with a total error of less than 0.1 sun diameters and provide a reduced aerodynamic profile to survive in high winds. They maintain the position of a receiver or a receiver-converter to the focus of the concentrated radiation to better than 0.1 sun diameters, and attempt to achieve minimum costs for manufacture, installation and maintenance. The known assemblies have aperture or collecting areas usually between 100 and 150 sq. metres although a few assemblies exceed 250 sq. metres.